Users get no benefit from the information resale directly, but they also aren't generally harmed by it. And the benefit they get from having a ubiquitously-connected device in their pocket outweighs the (apparently calculated to be low) per-person cost to their information being resold. The fact that you or I may do the calculus differently for ourselves (because we have different risk sensitivity) doesn't impact those who don't reach the same conclusions.
There may come a time in your life when you wish to have a say in the political system or are wronged by a powerful corporation. You'd care in that case. When your political rights disappear, they aren't easy to get back.
Which circles back to the original question: should a person feel guilt over creating tools that help the average user and harm the political dissident? Seems an open question. Perhaps one heavily dependent upon whether the actor agrees with the political dissident's position.
We should not be creating a mass surveillance state. The actual abuses domestically generally of minority populations, abroad, generally of non-NATO civilian populations, and potential domestic abuses (with many well noted assassinations and infiltrations in the past) are alarming and have already stronger, more precise abilities for social control of the population by the state than existed in dictatorships. The Stasi would have killed for the NSA's database and planting live tracking beacons on most citizens.
I'm on the left, but the non-financial political freedoms of the right are a bellwether for my own (though the literally genocidal far right is a more complex discussion). In general this makes a lot of logical sense because conservatives and right wing ideologues wish to maintain the status quo (literally to conserve it) or to return society to a past state (e.g. the relation of men and women, the role of religion, etc.), and range from libertarian to authoritarian, neither of which really threaten established authorities (and often reinforce them) and so are treated with kid gloves (watch how police treat right wingers at protests on average). Blue lives matter is a right wing cri de cœur that's an example of a "protest" that celebrates existing civil authorities.
Liberals and more-so leftists wish to change society into a new state which threatens the established order. Therefore, the civil authorities do not treat them with deference. Typically political freedoms lost by the right are applied with vengeance against the left.
Encourage dissent. We make fun of countries that don't. :)
EDIT: added info on why losses of political freedoms for the right are an especially bad bellwether
I'd like to ask anyone within RF earshot to carry my packets. I'd even consider paying for faster bandwidth if others were offering below some threshold. Some common low bandwidth communication should always work, say some fraction (split between freeloading users) of 20% of the link speed. I'll carry your packets if you're in earshot, rebroadcasting as needed, following the same rules. We could rotate our source addresses every so often.
You'd be persona non-grata (illegal) if you're recording and sharing who you hear. At the heart of it, saving and recording in perpetuity who you're communicating with and where ought to be illegal. Certainly selling that data should be too, or you end up with what we have today.
Yes, the UK absolutely needs additional dissent.
That seems like a terrible idea.
Because I'm not specifically aware there's a cross-town bus with my name on it, I'm somehow not about to get pancaked?